Safety gauging and sampling hatch



April 6, 1957 w. c. TODT ETAL 2,788,914

SAFETY GAUGING AND SAMPLING HATCH 2 Sheets-Sheet 1 Filed May 11, 1955INVENTORS' Af/V/VfT/l W. Cl/MM/N5 r /44M, c. roar TUE/Q ATTOQ/VEYiinited rates SAFETY GAUGING AND SAMPLING HATCH William C. Todt andKenneth W. Cunnnins, Odessa, Tex, assignors to Gulf Oil Corporation,Pittsburgh, Pin, a corporation of Pennsylvania Application May 11, 1955,Serial No. 567,667

4 Claims. (Cl. 226-29) This invention relates to an entry hatch for thetop or roof of a storage tank, and more particularly to a safety hatchfor access to an enclosed storage tank.

In the production and gathering of crude petroleum, the produced oil isconventionally stored in stock tanks prior to transmission to therefineries. In those areas where the crude produced i sour, that is,contains hydrogen sulfide, the gauging and sampling of the stock tankscan be hazardous to the operator because of the toxicity of the vaporsfrom the sour crudes. Similar problems exist where other liquidsemitting noxious vapors are kept in storage tanks, and it is necessaryperiodically to gauge or sample the tanks.

By the present invention, we provide a safety hatch permitting access tostorage tanks containing liquids which evolve toxic or noxious vaporswhereby the operator may gauge or sample the tank in safety withoutexposure to such vapors. in accordance with our invention, We provide asafety hatch for access to an enclosed storage tank, the safety hatchcomprising a hollow cylinder mounted in the top or roof of the tank, topand bottom closures for the cylinder, separate opening means forindependently opening the top and bottom closures, and locking meanspermitting only alternate opening of said top and bottom closures,whereby the bottom closure cannot be opened when the top closure is openand the top closure cannot be opened when the bottom closure is open.

Our invention will be further described with reference to the drawingsaccompanying this specification and forming a part thereof, in which:

Figure l is a view in front elevation of the safety hatch of theinvention showing the top closure open and the bottom closure closed;

Figure 2 is a view in rear elevation showing the top closure closed andthe bottom closure open;

Figure 3 is a view in side elevation; and

Figure 4 is a view along the line IVlV of Figure 3.

Referring now to the drawings in which like numerals indicate the sameelement in the various views, the safety hatch is designated generallyby the numeral 9, and comprises a hollow cylinder with a top closure 12and a laterally slidable bottom closure 22. The cylinder iii of thesafety batch is mounted in, that is, inserted part way through the roof11 of a storage tank and projects above the same. Projecting from thetop closure 12 is a handle member 29 for raising the top by hand. Alsoprojecting from the top closure are upright lugs 30 to which there isfixedly attached by a pin 31 an L-shaped hinge member 27. Hinge member27 is pivotally attached as at 13 by means of projection 32 to the outerwall of the cylinder 10. Fastened to the outside of cylinder it) arebrackets 15 and 17 which carry an elongated rod 15 rotatable about itslongitudinal axis, the rod extending from the position directly belowhinge member 27 to a point below the bottom of cylinder 19. A packinggland 18 guards against any leakage of gas at the point where rod 16enters the tank top 11. Rod 16 has a cap 14- at ice its upper end with aslot 28 therein for receiving and engaging the curved lug portion 279,of hinge member 27 when the top closure 12 is opened. The flat portion27b of hinge member 27 never engages the slot 28 and thus permitsrotation of rod 16 when the top closure 12 is closed. Rod 16 also has ahandle 23 adjacent its upper end and extending laterally therefromwhereby rod 16 may be rotated manually for opening and closing bottomclosure 22 which is attached thereto. Immediately below bracket 17, aflat bar 19 is fastened to the end of rod 16 and extends at right anglesto rod 16 across the bottom of cylinder 10. A pin 26 is fitted in a holedrilled in bar 19 at about midway of its length, the pin 28 extendingabove bar 19 and bearing bottom closure 22 rigidly attached thereto asby welding or other suitable means, as shown most clearly in Figure 3.Between bottom closure 22 and bar 19, there is provided a washer 33 toallow for a slight swivel action, thereby insuring a more positiveshutoff. The free end of bar 19 is capable of engaging a latch member21, which is fastened to the outside of the lower end of cylinder 10, tolimit the degree of rotation of rod 16 and its associated bottom closure22 to assure that the bottom closure effectively closes the cylinder 10when desired.

Immediately below top closure 12, as shown in Figure 1, there itattached a drain spout 24 by welding or other suitable means, and withinthe spout at the bottom thereof is a small drain hole 25 communicatingwith the interior of cylinder 19. At the upper edge of cylinder 10 thereis provided a slot 26 in the lip of the cylinder wall to permit entry ofeither a gauge line or thief line for gauging the tank or for obtaininga sample while the top closure 12 is closed. A roller wheel 34 for theaccommodation of such lines is located within the upper end of thecylinder 11 adjacent slot 26. The drain spout serves to catch drippingsfrom a gauge line being withdrawn through the safety hatch aftergauging; it may also be employed as a convenient receptacle for oilywaste used to wipe oh the gauge line.

In the operation of the safety hatch the top closure 12 is opened, thebottom closure being closed, and a thief for abstracting a sample or agauge for measuring the tank is placed within the cylinder 1% on a lineled over roller 34. While the top closure 12 is lifted so that theinterior of cylinder 1%) is open from above, the curved lug portion 27aof hinge member 27 is engaged in slot 28 of cap 14 on the upper end ofrod 16, so that it is not possible to rotate rod 16. Bottom closure 22therefore must remain closed. The operator is therefore not exposed tonoxious vapors from the interior of the tank. After a thief or gauge hasbeen placed within the cylinder 19 and the line attached thereto ledover roller wheel 34 and out through slot 26, the top closure 12 isclosed. Closing top closure 12 disengages the curved lug portion 272. ofhinge member 27 from slot 28 and rod 16 is thereafter free to rotate. Bymoving handle 23 is a clockwise direction (Fig. 4) through approximatelydegrees of arc, bottom closure 22 is opened thereby effectingcommunication of the cylinder 16 with the interior of the tank andenabling the thief or gauge previously placed within the cylinder 10 tobe lowered to the desired depth in the tank.

It will be noted that, when bottom closure 22 is open, the flat portion27b of hinge element 27 engages the upper extremity of rod 16, thuspreventing movement of hinge member 27 and any opening, adventitious orotherwise, of the top closure 12. The rod 16 is of suflicient length sothat its unslotted upper extremity permits such engagement. No noxiousvapors can therefore escape from the interior of the tank to thedetriment of the operator, notwithstanding the bottom closure beingopen.

the upper'end of cylinder 10.

Removal of the thief or gauge from within the tank is- 'form a seal withthe lower end of cylinder 10. Top

closure 12 is also advantageously provided witli ai gasket ring on itsinner surface effectively to form a seal with Drain spout 24 will serveto return to the interior of the tank, drippings from gauge line throughopening 25. Excess samples may be poured back into cylinder 10 when topclosure 12 is open. 7

Resort may be had to such modifications and variations as fall withinthe spirit of the invention and the scope of the appended claims.

' We claim:

l. A safety hatch for access to an enclosed storage tank comprising ahollow cylinder mounted in the top of said tank, a slidable closure forsaid cylinder, means for openingsaid bottom closure comprising anelongated rod capable of rotation about its longitudinal axis andattached to said bottom closure, a slotted head at the upper extremityof said rod, a top closure for said cylinde'r, a rigid hinge memberpivotally attached at one end to the outer wall of said cylinder andfixedly attached at its other end to said top closure, said hingenjember engaging said slotted head on said rod andvpreventing rotationthereof when said top closure is open, and said slotted head preventingopening of said top closure when the slot and hinge member are not inengagement.

2. A safety hatch for access to an enclosed storage tank comprising ahollow cylinder mounted in the top of said tank, a laterally slidablebottom closure for said cylinder, means for opening said bottom closurecomprising an elongated rod capable of rotation about its longitudinalaxis and attached to said bottom closure, said rod being positionedlongitudinally externally of said cylinder and journaled in bracketsattached to the outer surface of said cylinder, means for rotating saidrod, 21 slot in the upper extremity of said rod, a top closure for saidcylinder, a rigid hinge member for said top closure pivotally attachedat one end thereof. to the outer wall of said cylinder above the upperextremity of said rod and. fixedly attached at its other end to said'topclosure, a lug portion on said hinge member adjacent the point ofpivotal attachment thereof and adapted to engage said slot in the upperextremity of said rod, said rod being of suflicient length that theunslotted upper extremity thereof engages and prevents movement of saidrigid hinge member when said lug portion does not engage said slot.

3. A safety hatch for access to an enclosed storage tank comprising ahollow cylinder positioned part way through the roof of said tank, a topclosure hinged on said cylinder, the hinge thereof bearing a curved lugportion and a fiat portion, a rod positioned longitudinally or saidcylinder, having a slotted portion in its upper end for engaging saidcurved lug portion of said top closure hinge when said top closure isopen, the flat portion of said hinge being engaged by and renderedimmovable by the unslotted portion of said rod when the top closure isclosed, said rod being journaled in brackets attached to the outersurface of said cylinder, a handle extending laterally adjacent theupper end of said rod for manual rotation thereof when the top closureof said cylinder is closed, and a transverse bar attached to the lowerend of said longitudinal rod extending laterally therefrom below saidcylinder, said bar supporting a bottom closure for said cylinder, saidclosure being movable by rotation of said handle and saidlongitudinalrod to uncover the lower end of said cylinder.

4. The safety batch of claim 3, in which there is provided latchingmeans at the lower end of said cylinder adapted for engaging saidtransverse bar when the bottom closure is closed.

References Cited in the file of this patent UNITED STATES PATENTS1,169,606 Blank et a1. Jan. 25, 1916 2,065,019 Pedersen Dec. 22, 19362,261,457 Wiggins a Nov. 4, 1941 2,483,256 Berg Sept. 27, 1949

